High over the American Southeast, a Marine transport plane was cruising at 20,000 feet through clear skies when disaster struck.
A corroded propeller blade on the left wing of the KC-130T broke free, punching a gaping hole in the fuselage. That prompted a chain reaction in which a propeller on the opposite wing snapped away and cut through the aircraft. The plane disintegrated in explosions and plummeted into a soybean field near the Mississippi town of Itta Bena.
Those are among the findings of a Marine Corps investigation released Thursday about a July 10, 2017, crash that killed 15 Marines and one sailor. The service determined that the disaster was avoidable and was created by an unnoticed fatigue crack on the first propeller blade that broke free, resulting in the service's deadliest aviation mishap in more than a dozen years.
The plane - call sign Yanky 72 - never had a chance.
"Neither the aircrew nor anybody aboard the KC-130T could have prevented or altered the ultimate outcome after such a failure," Brig. Gen. Bradley James, the commanding general of the 4th Marine Aircraft Wing, wrote in his assessment of the crash.
The investigation renews questions about whether the U.S. military, after 17 years of war, is keeping up with the demands of maintaining an aging fleet of aircraft.
The report was released while U.S. and Japanese officials searched for survivors in an incident in which an F/A-18 Hornet and a KC-130 tanker plane appear to have collided during a refueling operation off the southwestern coast of Japan. As of Thursday, one Marine had been rescued, one was declared dead and five were missing.
The investigation of the Mississippi crash cites several groups for their handling of the aircraft before the crash, including Air Force aircraft maintainers at Georgia's Warner Robins Air Logistics Complex, where the corrosion on the first propeller blade that broke should have been noticed during the extensive service six years earlier.
Deficiencies in the overhaul process at Robins continued through 2017, prompting the U.S. military to temporarily ground dozens of similar planes, the probe concluded.
Investigators also questioned why the Navy Department did not discover deficient work on its aircraft at Robins sooner. And it said the unit responsible for the plane - Marine Aerial Refueler Transport Squadron 452 of Newburgh, New York - did not have a formal process for tracking manual inspections of propeller blades. It was not clear whether the crack had grown large enough for the squadron's maintainers to find it during routine safety checks, investigators found.
Other fatal incidents this year include a WC-130H transport plane crash in Georgia in May that killed nine members of the Puerto Rico National Guard, an Apache helicopter crash at Fort Campbell, Kentucky, in April that killed two soldiers, and the crash of an F/A-18F Super Hornet that went down in March off the coast of Key West, Florida, killing two Navy aviators.
Scores of service personnel have been killed in similar accidents over the past five years. A Military Times newspaper investigation published in April found that from 2013 to 2017, the number of aviation mishaps rose 39 percent, from 656 to 909. During the same period, the number of hours of training aviators received while airborne dropped because of the effects of congressionally mandated budget cuts and a need to keep available aircraft focused on operations, including the wars in Iraq, Afghanistan and Syria.
Senior Pentagon officials have said the trend does not constitute a crisis, but Defense Secretary Jim Mattis warned lawmakers last spring that the reduction in ready aircraft and time in the cockpit for pilots will take time to fix and require money. More recently, defense officials have suggested that they are starting to improve the availability of aircraft.
The plane involved in the Mississippi crash was 24 years old - younger than some U.S. military aircraft, but among the last T models of the KC-130 in the Marine Corps. The plane is due to be replaced by the newer KC-130J. The WH-130H that crashed in Georgia was more than 50 years old and making its last scheduled flight.
Among the dead in the Mississippi crash were seven members of an elite Marine Raider team from Camp Lejeune, North Carolina: Staff Sgt. Robert Cox, 28; Staff Sgt. William Kundrat, 33; Sgt. Chad Jenson, 25; Sgt. Talon Leach, 27; Sgt. Joseph Murray, 26; Sgt. Dietrich A. Schmieman, 26; and Navy Petty Officer 2nd Class Ryan Lohrey, 30. They were members of the Marine Special Operations Command (MARSOC), a force of less than 3,000.
The others killed came from the transport squadron. They were Maj. Caine Goyette, 41; Capt. Sean Elliot, 30; Gunnery Sgt. Mark Hopkins, 34; Gunnery Sgt. Brendan Jackson, 45; Staff Sgt. Joshua Snowden, 31; Sgt. Julian Kevianne, 31; Sgt. Owen Lennon, 26; Cpl. Daniel Baldassare, 20; and Cpl. Collin Schaaff, 22.
The disaster marked the second major loss of life in an aviation mishap for MARSOC in 28 months. In March 2015, a Black Hawk helicopter crashed off the coast of the Florida Panhandle, killing seven special operators from the same unit and four members of the Louisiana Army National Guard. A group of current and former Marine Raiders launched long marches from the crash sites back to Camp Lejeune in 2016 and 2018 to mark the anniversaries of the crashes.
The breakup of the aircraft over Mississippi required an extensive recovery effort in two separate debris fields separated by about a mile, the report said.